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. 2023 Mar 16;10(3):365.
doi: 10.3390/bioengineering10030365.

Strontium Ranelate Inhibits Osteoclastogenesis through NF-κB-Pathway-Dependent Autophagy

Dongle Wu  1   2 , Xuan Sun  1   2 , Yiwei Zhao  1   2 , Yuanbo Liu  1   2 , Ziqi Gan  1   2 , Zhen Zhang  1   2 , Xin Chen  1   2 , Yang Cao  1   2
Affiliations

Strontium Ranelate Inhibits Osteoclastogenesis through NF-κB-Pathway-Dependent Autophagy

Dongle Wu et al. Bioengineering (Basel). .

Abstract

Strontium ranelate (SR) is a pharmaceutical agent used for the prevention and treatment of osteoporosis and fragility fracture. However, little attention has been paid to the effect of SR on alveolar bone remodeling during orthodontic tooth movement and its underlying mechanism. Here, we investigated the influence of SR on orthodontic tooth movement and tooth resorption in Sprague-Dawley rats and the relationship between the nuclear factor-kappa B (NF-κB) pathway, autophagy, and osteoclastogenesis after the administration of SR in vitro and in vivo. In this study, it was found that SR reduced the expression of autophagy-related proteins at the pressure side of the first molars during orthodontic tooth movement. Similarly, the expression of these autophagy-related proteins and the size and number of autophagosomes were downregulated by SR in vitro. The results also showed that SR reduced the number of osteoclasts and suppressed orthodontic tooth movement and root resorption in rats, which could be partially restored using rapamycin, an autophagy inducer. Autophagy was attenuated after pre-osteoclasts were treated with Bay 11-7082, an NF-κB pathway inhibitor, while SR reduced the expression of the proteins central to the NF-κB pathway. Collectively, this study revealed that SR might suppress osteoclastogenesis through NF-κB-pathway-dependent autophagy, resulting in the inhibition of orthodontic tooth movement and root resorption in rats, which might offer a new insight into the treatment of malocclusion and bone metabolic diseases.

Keywords: NF-κB pathway; autophagy; orthodontic tooth movement; osteoclast; strontium ranelate.

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Conflict of interest statement

The authors declare that they have no known competing financial interest or personal relationships that could have appeared to influence the work reported in this paper.

Figures

Figure 1
Figure 1
Strontium ranelate suppressed osteoclast differentiation through autophagy in vitro. (a) TRAP staining images after pre-osteoclasts received different treatments for 5 days. (b) Monodansylcadaverine staining images after pre-osteoclasts received different treatments for 5 days. (c) Representative images of autophagosomes captured with a transmission electron microscope after pre-osteoclasts received different treatments for 5 days. Western blot assay and relative protein expression of the osteoclast markers TRAF6, c-Fos, MMP-9, MMP-14, and CTSK (d) and the autophagic proteins Beclin1, ATG5, LAMP2, LC3-I, LC3-II, and p62 (e) after pre-osteoclasts received different treatments for 5 days. (n = 3, mean ± SD, ** p < 0.01, *** p < 0.001).
Figure 2
Figure 2
Strontium ranelate inhibited osteoclast differentiation through NF-κB-pathway-dependent autophagy in vitro. (a) TRAP staining images after pre-osteoclasts received different treatments for 5 days. (b) Monodansylcadaverine staining images after pre-osteoclasts received different treatments for 5 days. (c) Representative images of autophagosomes captured with a transmission electron microscope after pre-osteoclasts received different treatments for 5 days. Western blot assay and relative protein expression of the osteoclast marker CTSK, the proteins central to the NF-κB pathway (p-IKKα/β, IκBα, and p65) (d), and the autophagic proteins Beclin-1, ATG5, LAMP2, LC3-I, LC3-II, and p62 (e) after pre-osteoclasts were treated with Bay 11-7082 for 5 days. (f) Western blot assay and relative protein expression of the proteins central to the NF-κB pathway after pre-osteoclasts were treated with SR for 5 days. (n = 3, mean ± SD, *** p < 0.001).
Figure 3
Figure 3
Strontium ranelate reduced orthodontic tooth movement and root resorption in rats. Three-dimensionally reconstructed micro-CT images of orthodontic tooth movement (a) and root resorption at the pressure side of the first molars (b) on days 3, 7, and 14 in different groups after orthodontic movement devices were established in rats. (c) HE staining images of root resorption at the pressure side of the first molars on day 7 in different groups. Quantitative analyses of orthodontic tooth movement (d), root resorption (e), and structure model index, thickness, bone volume/total volume, and trabecular space of the trabecular bone (f) at the pressure side of the first molars on days 3, 7, and 14 in different groups after orthodontic movement devices were established. (n = 5, mean ± SD, * p < 0.05, ** p < 0.01, *** p < 0.001).
Figure 4
Figure 4
Strontium ranelate inhibited osteoclast differentiation and the expression of osteoclast markers in rats. (a) TRAP staining images of osteoclasts and immunohistochemical staining images of RANK, OPG, c-Fos, TRAF6, MMP-14, NFATc2, and CTSK at the pressure side of the first molars on day 7 in different groups. (b) Number of osteoclasts and the mean optical density (MOD) of RANK, OPG, c-Fos, TRAF6, MMP-14, NFATc2, and CTSK at the pressure side of the first molars on days 3, 7, and 14 in different groups. (n = 5, mean ± SD, * p < 0.05, ** p < 0.01, *** p < 0.001).
Figure 5
Figure 5
Strontium ranelate regulated the expression of autophagic proteins in rats. (a) Immunohistochemical staining images of ATG5, Beclin1, LAMP2, LC3, and p62 at the pressure side of the first molars on day 7 in different groups. (b) The mean optical density (MOD) of ATG5, Beclin1, LAMP2, LC3, and p62 at the pressure side of the first molars on days 3, 7, and 14 in different groups. (n = 5, mean ± SD, * p < 0.05, ** p < 0.01, *** p < 0.001). (c) Immunofluorescence staining images of ATG5, Beclin1, LAMP2, LC3, and p62 at the pressure side of the first molars on day 7 in different groups. The white dashed lines indicate the margin of the tooth root.
Figure 6
Figure 6
Strontium ranelate suppressed the expression of proteins central to the NF-κB pathway in rats. (a) Immunohistochemical staining images of p-IKKα/β, IκBα, and p65 at the pressure side of the first molars on day 7 in different groups. The mean optical density (MOD) (b) and mean fluorescence intensity (MFI) (d) of p-IKKα/β, IκBα, and p65 at the pressure side of the first molars on days 3, 7, and 14 in different groups. (n = 5, mean ± SD, ** p < 0.01, *** p < 0.001). (c) Immunofluorescence staining images of p-IKKα/β, IκBα, and p65 at the pressure side of the first molars on day 7 in different groups. The white dashed lines indicate the margin of the tooth root.
Figure 7
Figure 7
Schematic illustration of the mechanism of how SR suppresses osteoclastogenesis by inhibiting autophagy through the NF-κB pathway.
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References

    1. Meyer-Marcotty P., Klenke D., Knocks L., Santander P., Hrasky V., Quast A. The adult orthodontic patient over 40 years of age: Association between periodontal bone loss, incisor irregularity, and increased orthodontic treatment need. Clin. Oral Investig. 2021;25:6357–6364. doi: 10.1007/s00784-021-03936-2. - DOI - PMC - PubMed
    1. Hirschfeld J., Reichardt E., Sharma P., Hilber A., Meyer-Marcotty P., Stellzig-Eisenhauer A., Schlagenhauf U., Sickel F.E. Interest in orthodontic tooth alignment in adult patients affected by periodontitis: A questionnaire-based cross-sectional pilot study. J. Periodontol. 2019;90:957–965. doi: 10.1002/JPER.18-0578. - DOI - PubMed
    1. Falgayrac G., Farlay D., Ponçon C., Béhal H., Gardegaront M., Ammann P., Boivin G., Cortet B. Bone matrix quality in paired iliac bone biopsies from postmenopausal women treated for 12 months with strontium ranelate or alendronate. Bone. 2021;153:116107. doi: 10.1016/j.bone.2021.116107. - DOI - PubMed
    1. Wirsig K., Kilian D., von Witzleben M., Gelinsky M., Bernhardt A. Impact of Sr and hypoxia on 3D triple cultures of primary human osteoblasts, osteocytes and osteoclasts. Eur. J. Cell Biol. 2022;101:151256. doi: 10.1016/j.ejcb.2022.151256. - DOI - PubMed
    1. Bonnelye E., Chabadel A., Saltel F., Jurdic P. Dual effect of strontium ranelate: Stimulation of osteoblast differentiation and inhibition of osteoclast formation and resorption in vitro. Bone. 2008;42:129–138. doi: 10.1016/j.bone.2007.08.043. - DOI - PubMed